In a conventional image forming device, a plurality of image formation units, which form toner images to be transferred onto a sheet, are positioned along a sheet carrying direction. The image formation units and transfer rollers are positioned to face each other across a carrying belt, which is positioned horizontally. A sheet stored with its image formation surface down in a sheet cassette positioned below the carrying belt is fed from the sheet cassette diagonally upwardly by sheet feeding rollers and is guided by a guide member. A front end of the sheet is nipped upwardly by a first carrying roller pair and directed to a second carrying roller pair by guiding the sheet in a turning carrying path that turns the sheet carrying direction by approximately 90 degrees. The sheet with its image forming surface facing up is nipped by the second carrying roller pair and carried onto the horizontal carrying belt. Toner images respectively formed by the image forming units are transferred onto the image formation surface of the sheet. (See JP Laid-Open Patent Application Publication No. 2008-50142, paragraphs 0015-0020, 0024-0027, and FIG. 2).
However, in such a device, the front end of the sheet is nipped upwardly by the first carrying roller pair and directed to the second carrying roller pair by guiding the sheet in the turning carrying path, which turns the sheet carrying direction by approximately 90 degrees. As shown in FIG. 14, a step is formed between a nip of the first carrying roller pair 101 and an upstream end of a carrying guide 103, which is located on an outer side of a curve of the turning carrying path 102. Therefore, after the front end of a sheet P that is nipped by the first carrying roller pair 101 and that is carried to the second carrying roller pair 104 as directed by the turning carrying path 102 is nipped by the second carrying roller pair 104, and at the moment when a rear end (or trailing end) of the sheet P is released from being nipped by the first carrying roller pair 101, a restorative force (in the direction of arrow A shown in FIG. 14) generated by the elasticity of the sheet tries to restore the original shape of the sheet. At that time, there is a problem that a hitting sound is caused when the rear end of the sheet P swiftly moves in the direction of the carrying guide 103 of the turning carrying path 102 due to the restorative force and strikes the carrying guide 103 at the time of sheet supply.
The present invention is created to suppress the above-discussed problem and has an object to reduce the hitting sound by the rear end of the sheet at the time of sheet supply by suppressing the flapping motion of the rear end of the sheet due to the restorative force of the sheet.